Boiler



April 14, 1925.

y L. C. LOEWENSTEIN ET AL BDILER [lill/III l April 14, 1.925. 1,533,706

l.. c. LoEwENsTl-:IN l-:T AL

\ BOILER Filed March 22, 1919 5 Sheets-Sheet 2 39 fr 37 5 5 FI. l TT? l n g 4 36a Fig. 5.

f 46 49 Inventors Louis C. Loewenstei n i Har-'ve N Davis,

by Vn/f 9h/ni Their' .fit-,horney 6 5 0 7, m 3 3 FD s l u e .m s 1u L A um N 1 R smh NIC. Emu w M E d o m L F C L.

April 14, 1925.

Fig` 8A.

sfvlllmllvlllll "mmmunmu Patented Apr. 14, 1925.

PATENT OFFICE.

Application led March 22, 1919. Serial No. 284,888.

To all whom t may concern:

Be it known that we, LOUIS C. LoEwEN-i STEIN, a citizen of the United States, residing at Lynn, count of Essex, State of Massa chusetts, and ARVEY N. DAVIS, a citizen of the United States, residing at. Cambridge, county of Middlesex, State of Massachusetts, have invented certain new and useful Improvements in Boilers, of which the followin is a specication.

he present invention relates to boilers, especially those intended for. vaporizing fluid having a high boiling point with respect to water and more especially to heavy liuids, such as mercury for example. ln such a boiler many character are presented which are not found in ordinary steam boilers. t

The object of our invention is to provide a boiler of improved construction and one which is eicient in operation.

For what we believe to be novel and our invention, attention is directed to the accom anying description and the claims appendbd thereto.

In the accompanying drawings, which are illustrative of our invention, Fi l is a vertical section of a mercury boi er, together with preheaters for the mercury and superheaters for the mercury vapor and also for steam; Fig. 2 is a plan view of the same with certain of the parts in section; F ig. 3 is a section taken on line 3 3 of Fig. 4; Fig. 3^ is a detail sectional view of a part of one of the boiler grids or cells; Fig. 4 is a view of a boiler grid or cell in elevation with certain of the parts broken away; Fig. 5 a view in sidel elevation of a number of boiler grids or cells, and Fics. 6 to l0 inelusive are detail views of dilferent parts of the boiler.

It will be helpful to an understanding of the invention if it be borne in mind that the boiler is primarily intended for use in a power generating system in which the mercury vapor is used to drive a turbine or other prime mover and the exhaust therefrom employed to generate steam from water problems of a complex.

which in turn is supplied to a turbine or other prime mover preferably of the condensing type, said turbines driving electric generators or other apparatus.

Briefly stated, in carrying out the invention, a plurality of grids or cells is provided which are supported within an enclosing casing in a manner to reduce heat strains to a minimum. The grids are all alike and each comprises two thin sheets of metal slightly separated to form liquid and vapor spaces. 'lhe sheets are sealed around their edges as by welding, electrically or otherwise where the liquid enters and the vapor is discharged. As thin sheets would bulge or buckle under pressure and heat they are united at a very arge number of points scattered over their the effect of mak- (preventing bulgentire surfaces which has ing them quite rigid and ing. This can readily be one in a variety of ways, as for example, by forming projections on one or both sheets and spot welding them. If liquid mercury were permitted to enter the grid at the bottom and escape at the top without any control of its movement the grid or cell would, of course, function as a boiler element but not very elliciently. To insure ell'ective circulation partitions are located rbetween the sheets of the grid, and they are so arranged that' the mercury and va or must flow a certain predetermined patli `or paths which bear a definite relation to the path or paths of the Hue gases. As arranged the liquid mercury is caused to ow along the bottom of the rid and as vapor is formed it flows upward or a predetermined distance and is then caused to flow downward toward the fire and then upward to the 'point of escape. In other words, the vapor has te make three passes before leaving the grid. In general, it is preferable to subdivide the vapor at some stage and cause it to discharge through two or more paths in multiple.

The flue gases are also caused to follow a predetermined path or paths which bear a very definite relation to the path of the vapor. To provide space for the due gases the grids must be separated from each other and this is done by placing separators be- 'simplifying it. In order to tween them, which separators may be constructed in a variety of ways. They are preferably made in the form of partitions and are employed to form definite flue gas passages. As arranged hot gases from the furnace enter the flues at the bottom, pass upward to the top of the grids and are then turned and caused to flow downward to a point near the bottom and finally escape y lateral passages into an outer compartment. In other words, the flue ases make a double pass in lowin from t e furnace to the oint of escape. uring the first portion o their path they flow in the same direction as the mercury Ivapor but in the latter part the flow in the opposite direction and in this manner are caused to give up the greater part of their heat. Since the gases contain a large amount of heat after evaporating the mercury, a necessary evil due ,to its high boiling point, they may advantageously be employed to superheat the mercury vapor, preheat the mercury and superheat steam when the latter is used in a-portion of the complete cycle.

The sheet `or plate construction for the grids or cells has the advantage that the parts may be stamped out of sheet stock at a small expense after the dies are made and said dies are of sim le construction. The plate construction a so results in a rapid transfer of heat from the ilue gases to the liquid in the cell or grid. This ra id transfer of heat is due not only to the fliin walls of the grids but also to the fact that the liquid and the vapor released thereby flow through the grids in relatively Wide and very thin streams. The use of welded buttons, indentationsdor equivalents securing devices not only provides separators between the sheets but affords a simple means for uniting the sheets and adds greatly to their mechanical strength. By combining a mercury preheater element with each grid or cell it can be formed at the same time the sheet is formed and this results in a. considerable simplification of the structure as a whole. Furthermore, by making a grids alike, they can be replaced quickly and economically in the event of injury.

Instead of employing individual separators between the grids or cells to form ilue s spacesthe plates themselves may be ribbed or corrugated or otherwise formed so that when assembled into the complete boiler the ribs or corrugatons act as separators. This has the advanta e that t e separators also serve as strengt ening ribs for the sheets and the use of separate attaching means is avoided thus materially rcducing the cost of construction and greatly reduce the amount of heat insulation as much as, pos- |chamber 27 which comp ll Steam is admitted by the pipe 31,

vaisaa'roe sible a double casn boiler and the air w tion ows between entering the burner.

Referring to the drawings, 21 indicates a boiler casing of any suitable construction which is suitably lagged at 21Il to prevent the escape of heat. nside the casing is a plurality of boiler grids 22 `each comprising two sheets of metal suitably united as by welding along their edges to form spaces or passages for the liquid inercury and the vapor due to evaporation thereof. These grids are placed sideby side and are suppgrted by suitable means such as the throu h lts 23 which pass through ears 24 in t e ted by the walls of the iler casing. In other words the grids are hung on these bolts and are free to expand and contract in all directions in accordance with temperature changes, without causing undue stresses. Below the grids is a burner or furnace 25 of suitable construction. In this case it is shown as a gasolene burner to which fuel is supplied at one or more points by a suitably arranged pipe 26. Air to support combustion is sup ied from the air is provided for the ich supports combusthe two casings before gids and are supper boiler grids and is formed by the inner casing wall'28 Aand the outer wall 21. arrangement causes the air admitted to the furnace to be preheated and in this manner additional heat is extracted from the flue gases. The exhaust products of combustion escape from the inner casin by the outlet or stack 29. Air may be gereed into the chamber 27 under pressure to aiord the necessary draft or the stack 29 may be connected to a suitable chimney for the purose. Located within the inner casing is a superheater 30 for the steam evaporated from the water used as the condensing a nt for the mercury vapor after it has one work, as for example, in a mercury turbine. The superheater iscomposed of a number of units of which two are shown and located on opposite sides of the grids. As shown each unit comprises a coil of pipe or pipes but it may be made in avariety ofFways.

i 2 ows upwardly through the two oppsitd sections of the steam superheater in multiple, and is inally discharged through pipe The boiler ids are se aratcd from each other b smal vertical ues 33 which are relative y thin and wide and through which the gases flow at a rapid rate. These flues are formed by central partitions 34 and other arttions 34 on opposite sides thereof, said partitions taking the form of ribs on o posite sides of each may formed on one or both sheets. It is advantageous to form them on both sheets because the metal will not have to flow so sheet. The ribs struction of discharged much under the die and hence the id may e more easily formed. The hot gli-e from the burner iirstfiow upwardly between the partitions 34 and 34l1 and then turn and dow downwardly between the partitions 34a and the outer walls which in this case are formed by mercury preheaters which will appear more fully later. These 'preheaters outlet openings or passages 35 (Figs. 1 and 4) between them near the lower ends to pei-- mit the hot gases to enter the steam superheating chambers through which they pass upwardly to the stack 29. The ath of the flue gases is indicated by the full ine arrows and it is to be understood that similar passages are provided between each pair of boiler grids. The flue gases are prevented from escapin at the top of the grids by anges 51 an 53 on the sheets, Figs 8 and 9, and by a layer or covering of insulating material 36, best shown in Figs. 4 and 5.

The mercury vapor generated within the grids flows ultimately into the superheater 37 which extends across the top of the grids and is connected to the vapor spaces thereof. liese s aces are indicated at 38 in Fig. 2. From t e construction described it will be apparent that the several grids feed mercury vapor to the super-heater in multiple. Preheated mercury is supplied to each of the grids from opposite sides by individual reheaters 34b and the latter are connect in multi le to headers as will appear more fully Ilater. Superheated mercury :vapor is to the turbine by the outlet pipe 39. The superheater is subjected on its under side to the flue gases which t e Hue gases are caused to give up their heat in vaporizing the mercury; in preheating the mercury; in superheating the mercury; in superheating steam, and in preheatin the air passing to the burner through the c ber 27. In this manner the heat of the gases is eifectively utilized and very little permittedto escape through the outer casing. Un-

er some circumstances it will be possible to utilize the heat from the of the com lete cycle. fic construction ofp described. Each grid comprises two thin sheets of metal l42-43, Figs. 3, 6 and 9, which are welded otherwise along their edges except for the portions forming the inlets om the preheaters and the outlets 38, Fig. 2, leading to the superheater. To prevent the plates from buckling as they otherwise wou d do and also to form definite spaces for the liquid mercury and the vapor thereof, we provide partitions or separators between 34", the con-i or side walls have t in Fig. 4 indicating the the boiler grid h electrically or th the H lates such as 44 and 45, shown in dott-ed ines, Fig. 4. The artitions 44 are substantially L-shaped in orm and liquid mercury from the preheaters 34h enters the boiler space below the partitions where the gases are hottest, being direotl above the burner, an

lower end of the partition 45 and flows upwardly through the outlets 38 to the superheater 37.

As previously indicated the plates of the i s are very thin and to prevent them rom separating they are electrically spot welded over their entire surfaces as indidicated at 52, the small crosses and circles welds. These welds should be of small area so that the heat of the flue gases at the points of metal contact can be readily absorbed by the mercury. If the welds are too large or the vapor passage is unduly restricted at or near these weld's the plates will be burned out for the temperatures are very high and the metal forming the sheets very thin.

To form the mercury preheatcr and also the partitions between adjacent grids the sheets 42 and 43, Figs. 3 and 6, are provided rejections or ribs 34, 34a1 and 34 and the edJges of the sheets are welded together at 46. The grids when assembled are so arranged that correspondin ribs engage and in this manner vertical uc spaces 33 are formed. e spaces for the mercury vapor are indicated at 48 and it will be seen that t ey are very thin but relatively wide and 'due to this arrangement the heat of the Hue,

gases is ver readily cury. The ower end tition or separator 34a at the point 49, Fi s. 3A and 4, to prevent t e mercury from t e lpreheater from short circuitin its main pat Each rid has its own preeaters 34", walls of which are integral with the sheets, the upper ends of which terminate in a header 49l which is common to all ofthe preheaters on that side. The )oints between these parts should be welded to insure Huidtight connections. The relation of the eader and the preheaters is well illustrated Fig. 7 clearly shows given up to the merof the outer rib, parin Figs. 4, 5, 7 and 10. the supporting ears 24 for the grids and p orting bolts 23 on which they are lo se arate the sheets 42, 43 of each along t eir beveled upper edges inned spacers 50 are provided which may be welded to the esu hun.

ico

is pinched or welded .iic

which prevents the free escape of heat and also serves to cover upwany spaces between rids which may have en left in the welding o ration and to this extent helps to define t e iiue gas passages or spgces.

Fig. 6 shows one of the iler grids in section and specifically shows how the spot welds 52 are forme s shown one oi the sheets is provided with a series of buttons 52 which are small in diameter and in addition to formin welding points also serve as separators to crm the mercury vapor spaces. lVlien properly welded the buttons also serve as means to reinforce the slieetsand keep them from buckling.

Fig. 8 shows the mercury vapor superheater 37. The sheets at this point have outturned edgesor flanges 53 which are welded to a plate 54 forming the bottom wall of the superheater. In the plate are openings registerin with the vapor spaces 38. The upper wa 155 of the superheater is also welded to the plate 54.

Our improved boiler has man advantages, among others that of a sma l storage S ace for the relatively costly fluid. Furt er, the heatin thin metal whic weight for a given output. By the arrangement of the various passages for the Huid,

vapor and fiue gases, we obtain a very rapid transfer of heat from the gases to the iiuid and its vapor and also a veryq rapid circulation of both the fluid and t e vapor which latter obviates the danger of burning out the heating surfaces. The liquid in the boiler is confined in very narrow s aces or passages and is subjected to very igh tem erature, the advantage of which as we ave demonstrated in experiments is that the generation o vapor is ex lesive in character with the result of comp stream.

transfer of heat from liquid. As fpreviously stated the boiling point of the uid is high compared with that of water and hence the flue gases even after the vapor is formed contain a substanti l amount of heat but by arranging the parts as described, this heat is utilized in a manner to substantially improve the eiiciency oi' the boiler unit as a whole.

In accordance with the provisions of the patent statutes, we have described the princi le of operation of our invention, together with the apparatus which we now consider to represent the best embodiment thereof; but we desire to have it understood that the apparatus shown is only illustrative, and that the invention can be carried out by other means.

What we claim as new and desire to secure by Letters Patent of the United States, isz- .means separating the grids to i 1. In a boiler, the combination of a casing, a plurality of grids each com rising f sheets of thin metal uni a pair o their edges, separators between the sheets spaces,

forming efmite liquid and vapor for the fine gases, a super-heater into which the grids discharge vapor, and which is supported by the grids and heated by the flue gases, the grids within the casing, ceding liquid to each of the grids, and an outlet for the vapor which communicates with the super-heater.

2. In a boiler, the combination of a casing, a plurality of grids, each comprisin thin sheets of metal having a liquid an vapor space therebetween, rojections on each pair of sheets which w en assembled cooperate to form a preheater, the said sheets being welded along the edges outside of tlie preheaters and also between the preheater and the vapor space, means separating the grids to form due gas spaces, a conduit admitting liquid to the preheater, and a conduit receiving vapor from said vapor spaces.

8. In a boiler, the combination of a casing, a plurality of grids, each com rising thin sheets of metal havin a liqui and vapor space between, projections on op osite sides of each pair ci' sheets which w en united form pre ieaters for the fluid, the projections on one grid engaging those on adjacent grids when the pai ts are assembled and forming the boundary walls of the flue gas passages, additional separators between the grids which also assist in deiining the Hue gas passages, and conduits conveying liquid to the grid and vapor therefrom.

fi. In a boiler, the combination of a casing, a plurality of grids, thin sheets of metal having li uid and vapor spaces between, prelieaters or the li uid formed by the sheets along certain of Jlieir edges, there between the grids, and means grids within the casin said grids and the pre pand v and contract changes.

5. n a boiler,

eaters can freely exwith temperature the combination of a casing, a plurali?Y of grids, each comprisin thin sheets o metal having liquid and vapor s aces between, said sheets having outward y extending projections which when the arts are assembled form preheaters for the iquid and also separators to form ue gas passages, and rods supported by the casing and upon which the grids are supported near one end to permit of free expansion and contraction.

6. In a boiler, the combination of a plurality of sheet metal grids, each comprising a pair of thin inetal sheets, individual pre-heaters for each grid located on opposite each comprising edges and'communicating' /with the spaces between/the sheets, spaers between each pair of sheets forming liquid and vapor spaces, separators between the gridsforming flue gas spaces, a super-heater mounted directly on the grids and .welded to said sheets and into Wheh the grids discharge vapor-in multiple, and headers for supplynn liquid to the pre-heaters.

in' witness whereof, we have hereunto set` 10 our hands this 20th day of March, 1919.

L`0UIs C, LOEWENSTEIN.' HARVEY N; DAvs.

edges and ,communicating with the spaces vapor in I'nulti le, and headers for supplybetween/tiie sheets, spacers between each in .liquid to t e pre-heaters.

pair of sheets forming liquid and vapor spaces, separators between the grids formour hands this 20th dey of Merch, 1919. in'g `flue gas s aces, a super-heater mounted directly on t e grids and welded to said sheets and into whih the grids discharge L`0U1s c. LOEWENSTEIN; HARVEYy N. DAVIS.

certificate of Correction.

Ib is hereby certified that, in Letters Patent'No. 1,533,706, granted April 14, 1925, npon the application of Louis C. Loewensten, of Lynn, undHarvey N. Davis, of Cambridge, Massachusetts, for an improvement in Boilers, errors appear in the printed specieation requiring correction :is follows: Page 1, line 61. after the word otherwise insert the word l'rrwpt, und liner 79, after the word flow insert the word along; page 4, linee| 21S-459, for the word temperatureread temperatures; and that the snif] 'Letters Patent should be read with these corrections therein that the same may conform lo the'record of the casein the Patent iiice.

Signed and sealed this 12th day of Ma-y, A. D. 1925. u i

[SEAL] KARL FENNING,

` Acting Gommxssioner of Patents.

n witness whereof, we have hereunto Vsei: 10

Certcate of Correction.

YIt is hereby certified that. in Leiters latnt No. l,."lI,TlKi, grunted April 14, 1925, upon the np lication of Louis C. Locwensten, of Lynn` und Harvey N. Davis, of Cambrl ge, Maachusetts, for an improvomont, in Boilorsf errors appear in the printed specification rcqnirinpr corrmtion ns follows: Png@ l1 line 6|. afhl the word otherwise inslrt thv wol-(l r'zr'rffpt, und lnv. 79, ufirr lln' word How insert the wurd along.' page 4. lines 392-39, for llw wurd temperature read lempffmhu'ex; und tl these corrections therein that th in the Patent Oce.

Signed and sealed this 12th day of May, A. D. 1925.

e same may conform lo thr'record of the casti KARL FENNING, Acting Uormnsioner of Patents.

lat the .unid Lelie-rs Patent. should be read with 

